1. Field Of The Invention
The present invention relates to a bare printed circuit board tester, and more particularly, to a bare printed circuit board tester for simultaneously testing a large number of conductive paths on a bare printed circuit board for open circuit and short circuit conditions.
2. Description Of The Prior Art
The testing, checking, verifying, and/or "buzzing" of each of a large number of conductive paths on a bare printed circuit board or the like with a multimeter or by visually scanning the printed circuit board has previously been used in the prior art for testing for both short circuit and open circuit conditions. Typically, such prior art tests and test systems are neither cost effective nor reliable, and they result in a great loss of time and added expense of the finished printed circuit board. Nonetheless, such methods continue to be used with a large number of circuits produced by at least the smaller printed circuit board manufacturers today.
While some types of computer-controlled testing systems are used for testing printed circuit boards, they are extremely complex, time consuming, and expensive. For example, the cost of such systems is generally in the range of hundreds of thousands of dollars, or ten or more times the cost of the present system.
It is, therefore, an object of the present invention to provide a method and apparatus for simultaneously testing for both short circuit and open circuit conditions in a bare printed circuit board having a large number of conductive paths, with the testing of the conductive paths being done simultaneously so that open circuits and short circuit conditions can be quickly detected and visually located for all of said conductive paths under test in an extremely short period of time, such as under five seconds.
It is a further object of the present invention to provide a relatively low cost system for performing short and open circuit tests in a minimal amount of time.
It is still a further object of the present invention to provide a method and apparatus for testing for shorts and opens for a large number of conductive paths while simultaneously visually indicating both the presence of shorts and opens and the location thereof on an LED display panel.
It is still a further object of the present invention to provide voltage divider circuitry to enable a relatively large value of DC voltage to be applied to the LEDs for driving an extremely large number thereof without damaging the remainder of the circuit.
It is a further object of the present invention to provide a test station wherein a simple change in the terminal-engaging contact board can be made for testing a different bare printed circuit board simply by programming a new terminal-engaging contact board from the artwork used to generate the new printed circuit board to be tested.
It is still a further object of the present invention to provide a quick and efficient confirmation of assembly quality of bare printed circuit boards while allowing rapid AQL or even 100% testing on incoming printed circuit boards.
It is still another object of the present inventior to provide a test device which enables a field service person to quickly locate and identify short circuit and open circuit conditions in the field or on site by a mere visual scanning of the instrument.
It is yet another object of this invention to provide a shorts and opens tester which can be used in the manufacture of multilayered printed circuit boards to test each layer separately before the next is added.
It is still another object to provide a method and apparatus for simultaneously testing all conductive paths in even the most complex bare printed circuit boards quickly and accurately.